Reagent mixer



Aug. 30,1938.v D. M. WRIGHT 2,128,447 n f REAGENT MIXER l Filed Nov) 2s,195e z sheets-sheet 2 s l f ...A u *Il 25. /H i miam "u Ffh| L Elli 9:22f "\V i r l'f1/f4 ATTORNEY Patented Aug. 3o, 193s VPATENT OFFICE REAGENTMIXER David M. Wright, Agricola, Fla., assignor to Industrial PatentsCorporation, Chicago, Ill., a corporation of Delaware ApplicationNovember 23, 1936, Serial No. 112,406

2 Claims.

This invention relates to a reagent mixer. One of the objects of theinvention is to provide mixing apparatus for mixing reagents withphosphate rock feed.

Another object of the invention is to provide a eddy currents..

Other objects of the invention will be apparent from the description andclaims which follow.

I n the mining of. phosphate rock, for example in the Florida fields,the matrix is removed `from an' open pit mine by hydraulic miningmethods. Material in the form of a wet slush is pumped over a washer,which consists of lugs and screening and settling apparatus, by means ofwhich screening and settling apparatus the pebble phosphate is removed.Ihe tailings from the washer have traditionallybeen delivered to thedebris dumps.

In recent years, various recovery methods have been applied to recoverthe phosphate values from the washer tailings, since large percentagesof phosphate values in the matrix exist in particle size such as toprevent eifective screening. An example of recovery methods is thefamiliar flotation method, with which recovery is effected by mixingreagents such as oil, sh acid and caustic with the tailing to formfioccules of phosphate values, which may be floated by beating in air.Due to the relatively low value of the mineral values recovered, it isimportant in such recovery methods that reagent quantities be kept at aminimum. This necessitates high efficiency in mixing the reagents withthe feed.

The present invention provides an eilicient mixing apparatus whichgreatly reduces reagent costs and increases effective recovery.

A preferred embodiment of the mixing apparatus of the present inventionis shown in the drawings in which similar characters of reference in theseveral figures indicate similar parts.

Figure 1 is a plan view of a mixing battery.

Figure 2 is a view, partly in section, of the mixer shown in Figure 1.

Figure 3 is a plan view showing a modified form of mixer in whichadjustable baiiles are employed to control material flow.

Figure 4 is a view, partly in section, of the mixing battery shown inFigure 3. l

To secure thorough mixing, it is desirable to employ more than asinglemixing chamber. Eiective mixing,- may be secured by employing two mixingchambers. The feed coming through pipe I passes into vessel 2 and isstirred by agitator 55 blades 3 mounted upon shaft 4 iournalled in mixerso constructed as to prevent by-passing of y bushing 5 fixed by collar6. Shaft 4 is provided with gear 1 drivenr by worm 8 mounted upon driveshaft 9. The vessel I0 is provided with agitator blades II mounted uponshaft I2, journalled in bushing I4 fixed by collar I5. Shaft I2 visprovided with gear I3 driven by worm I8 mounted upon drive shaft 9.Similarly, power on shafts 4 and .I2 by bushings Il and I8 attached tomain bushings 5 and I4. Material entering vessel 2 is thoroughly mixedtherein, is passed through opening I9 into vessel Ill and thence outpipe whence it may be led to flotation cells or other apparatus.

It will be seen that the vessels-are cylindrical and are provided at thebottom with rounded, concave corners. The rounded corners 2I presentcurved circumferential surfaces relative to the zone of. operation ofthe agitator blades andthus cooperate with the agitator blades toprevent the setting up of eddy currents in the vessels and to assurethorough, rapid mixing. A reagent may be added to the feed at anydesired point along line I although it is preferable to add the reagentby continuous dropping directly into vessel 2.

If desired, the ilow of material from vessel 2 to vessel I0 and fromvessel I0 through pipe 20 may be controlled by adjustable baffles 22 and23, respectively, as shown in Figures 3 and 4. Sleeves 24 and 25 ofbafiles 22 and 23 ride upon collars 25 and 21. Handles 28 and 29 areplaced in any desired groove 30 to fix the bailies in position. Prior tothe present invention, it has been customary in the mining industry -toemploy square mixers, which were thought to have a special virtue ineffective mixing. I have found that a cylindrical, stationary mixer witha closed bottom and in a vertical position with a vertical shaft issuperior to the conventional square mixer. I have also discovered thatthe cylindrical mixer may be operated on phosphate rock feed with a muchsmaller quantity of water in the feed than may be effectively employedwith a square mixer of similar dimensions and agitated by motors of thesame rating.

If the amount of moisture in feed with which the cylindrical mixeroperates satisfactorily were employed in the conventional square mixer,the motor would be unable to pull the load and be stopped. As a directresult-of the great reduction in the amount .of moisture required in thecylindrical mixer, thev cylindrical mixer of the present invention hasresulted in greatly increased recovery percentages in the treatment ofphosphate rock feeds.

Attention is directed to the shape oi the bottom of the mixing vesselswhereby with rounded corners stagnant eddy currents are eliminated.

In the use of the mixing apparatus of the present invention, asubstantially dewatered feed in the form oi' a slush is subjected tosuccessive, continuous, circular agitation accompanied by the continuousaddition of reagents, after which the treated feed is subjected toconventional recovery processes such as flotation, tabllng, underwaterscreening, skin ilotation, or the like.

I claim:

1. In a mixing device, a battery of cylindrical vessels mounted in thesame horizontal plane and interconnected with one another throughcommunication openings located near the top edges of the respectivevessels, each of said vessels being provided with a vertical side wall,a ilat bottom and a continuous rounded corner between the side wall andbottom, and an agitator comprisingl a. plurality of radially extended,angular-ly inclined blades, rotatably, coaxlally mounted within each ofsaid vessels, the blades of each agitator being positioned closelyadjacent the bottom and extended within the zone of the rounded cornerof the respective vessel,the

blades of the agitator of each vessel being adapted to swirl a slushmixture upwardly against the side wall of the respective vessel, theswirled matertal being passed to the next succeeding vessel through therespective communication open- 2. In a mixing device, a battery oicylindrical vessels mounted in the same horizontal plane andinterconnected with one another through communication openings locatednear the top edges of `the respective vessels, each of said vesselsbeing providedwith a vertical side wall, a ilat bottom and a continuousrounded corner between the side wall and bottom, an agitator comprisinga plurality of radially extended, 'angularly inclined blades, rotatably,coexially mounted within each of said vessels, the blades of eachagitator being positioned closely adjacent the bottom and extendedwithin the zone of the rounded corner of the respective vessel, theblades of the agitator of euh vessel being adapted to swirl DAVID M.'WRIGHT.

succeeding vessel.

